What are ballistics?


Ballistics define how the meter "reacts" to changes in the measurement of audio.


There are very specific "rise" and "fall" times for different ballistics, each for their own use:


Faster rise times are good for monitoring peaks, while slower rise times are good for monitoring average values.

Fall times are matched either to the response of the ear, or to some arbitrary rate which makes it easier to see peaks.

Hold times are good for a "peak hold" effect, to be able to see the level of a high value for many seconds after it occurred.


All of these values combined create different "reactions" for meters and are vital to the attractiveness and usefulness of a meter.


Digital


The digital meter is a very useful standard meter in the digital realm. It moves relatively quickly with audio levels, and is moderately difficult to achieve in an analog counterpart. It borrows the rise time from PPM I level meters, but has a faster fall time.


It will respond to higher levels by rising 9.6dB every 1.7ms until it reaches the audio level

It will respond to lower levels by falling 20dB every 850ms until it reaches the audio level


VU


The VU ballistics were designed for the VU meter needle, and are modeled after the response of the human ear (apparently).


It will respond to higher levels by rising 40dB every 300ms until it reaches the audio level

It will respond to lower levels by falling 40dB every 300ms until it reaches the audio level


PPM Type I


The PPM Type I ballistics were one of the original meter ballistics used on professional digital meters.


It will respond to higher levels by rising 9.6dB every 1.7ms until it reaches the audio level

It will respond to lower levels by falling 20dB every 1.7s until it reaches the audio level


PPM Type II


The PPM Type II meter was one of the original meter ballistics used on professional digital meters. It distinguishes itself from the PPM Type I by its slower fall time and a slight hold time.


It will respond to higher levels by rising 9.6dB every 1.7ms until it reaches the audio level

Once reaching the peak audio level, it will hold its mark for 0.1s

It will respond to lower levels by falling 24dB every 2.8s until it reaches the audio level


Nordic


The Nordic ballistics were designed to work with meters using the Nordic scale.


It will respond to higher levels by rising 14dB every 5ms until it reaches the audio level

It will respond to lower levels by falling 20dB every 1.5s until it reaches the audio level


BBC/EBU


The BBC/EBU ballistics are mainly used with meters using the BBC scale. It is similar to the Nordic scale, but with a slightly different fall time.

It will respond to higher levels by rising 14dB every 5ms until it reaches the audio level
It will respond to lower levels by falling 24dB every 2.85s until it reaches the audio level